Chapter 15

Basic Data Analysis: Descriptive Statistics

Coding Data and the Data Code Book

• Data entry: refers to the creation of a computer file that holds the raw data taken from all of the questionnaires deemed suitable for analysis

• Data coding: refers to the identification of codes that pertain to the possible responses for each question on the questionnaire

• Data code book: identifies all of the variable names and code numbers associated with each possible response to each question that makes up the data set

Types of Statistical Analyses Used in Marketing Research

Data Reduction

• Data reduction: the process of describing a data matrix by computing a small number of measures that characterize the data set

• Four functions of data reduction:• Summarizes the data• Applies understandable conceptualizations• Communicates underlying patterns• Generalizes sample findings to the population

Types of Statistical Analyses Used in Marketing Research

Statistical Analysis

Types of Statistical Analyses Used in Marketing Research

Statistical Analysis

• Five types of statistical analysis: • Descriptive analysis: used to describe the data set• Inferential analysis: used to generate conclusions

about the population’s characteristics based on the sample data

• Differences analysis: used to compare the mean of the responses of one group to that of another group

• Associative analysis: determines the strength and direction of relationships between two or more variables

• Predictive analysis: allows one to make forecasts for future events

Understanding Data Via Descriptive Analysis

• Two sets of descriptive measures:• Measures of central tendency: used to report a

single piece of information that describes the most typical response to a question

• Measures of variability: used to reveal the typical difference between the values in a set of values

Understanding Data Via Descriptive Analysis

Measures of Central Tendency

• Mode: the value in a string of numbers that occurs most often

• Median: the value whose occurrence lies in the middle of a set of ordered values

• Mean: sometimes referred to as the “arithmetic mean”; the average value characterizing a set of numbers

Understanding Data Via Descriptive Analysis

Measures of Variability

• Frequency distribution: reveals the number (percent) of occurrences of each number or set of numbers

• Range: identifies the maximum and minimum values in a set of numbers

• Standard deviation: indicates the degree of variation in a way that can be translated into a bell-shaped curve distribution

Understanding Data Via Descriptive Analysis

Measures of Variability…cont.

When to Use a Particular Descriptive Measure